Recently donated blood when blood was tested in lingered instead of sunk, did test for anemia but tested negative - what could the floating blood mean?

More than one thing: It may be that your hemoglobin levels is at the borderline of normal and low. It may be due to high lipids in your blood. You may wish to consult your doctor for follow-up tests and explanation. I commend you for your altruism and donating blood. For good health - Have a diet rich in fresh vegetables, fruits, whole grains, milk and milk products, nuts, beans, legumes, lentils and small amounts of lean meats. Avoid saturated fats. Exercise at least 150 minutes/week and increase the intensity of exercise gradually. Do not use tobacco, alcohol, weed or street drugs in any form. Practice safe sex. Get HPV vaccine.